function template
<locale>
std::isdigit
template <class charT> bool isdigit (charT c, const locale& loc);
Check if character is a decimal digit using locale
Checks whether c is a decimal digit character using the ctype facet of locale loc, returning the same as if ctype::is is called as:
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use_facet < ctype<charT> > (loc).is (ctype_base::digit, c)
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This function template overloads the C function isdigit (defined in <cctype>).
Parameters
- c
- Character to be checked.
- loc
- Locale to be used. It shall have a ctype facet.
The template argument charT is the character type.
Return Value
true if indeed c is a decimal digit character.
false otherwise.
Example
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// isdigit example (C++)
#include <iostream> // std::cout
#include <string> // std::string
#include <locale> // std::locale, std::isdigit
#include <sstream> // std::stringstream
int main ()
{
std::locale loc;
std::string str="1776ad";
if (isdigit(str[0],loc))
{
int year;
std::stringstream(str) >> year;
std::cout << "The year that followed " << year << " was " << (year+1) << ".\n";
}
return 0;
}
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Output:
The year that followed 1776 was 1777.
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Data races
Both loc and its ctype facet are accessed.
Exception safety
Strong guarantee: if an exception is thrown, there are no effects.
See also
- ctype
- Character type facet (class template)
- isdigit (cctype)
- Check if character is decimal digit (function)
- isalnum
- Check if character is alphanumeric using locale (function template)
- isalpha
- Check if character is alphabetic using locale (function template)